Frequently Asked Questions

Results are estimates based on validated scientific formulas (Mifflin-St Jeor, WHO BMI, NIH RDA). They are accurate for most healthy adults within ±10%, but individual factors like genetics, medications, and muscle mass can affect real values.

No. All calculations happen in your browser using JavaScript. No personal data is ever sent to our servers or stored anywhere.

We use the standard WHO BMI formula: weight(kg) ÷ height(m)². For children aged 2–20, BMI should be interpreted using CDC age-specific percentile charts rather than adult ranges.

We use the Mifflin-St Jeor equation (1990) as the default, which is considered the most accurate for estimating BMR in most adults per the American Journal of Clinical Nutrition.

Some calculators include pregnancy-relevant adjustments (protein, weight gain). For all health decisions during pregnancy, please consult your OB/GYN or midwife.

BMR (Basal Metabolic Rate) is the calories your body burns at complete rest to keep organs functioning. TDEE (Total Daily Energy Expenditure) is your BMR multiplied by your activity level — your actual total daily calorie burn.

Use the unit toggle tabs at the top of any calculator — choose 'US/Imperial' for lbs/ft/in or 'Metric' for kg/cm.

BMI Prime is your BMI divided by 25 (the upper normal limit). A value below 1.0 means normal weight; above 1.0 means overweight or obese.

BMI for children (ages 2–20) uses age-and-sex-specific percentile charts rather than adult ranges. Other calculators (TDEE, protein) are designed for adults aged 18+.

Recalculate whenever your weight changes significantly (more than 2–3 kg) or your activity level changes. TDEE and BMR are estimates that shift with body composition changes.

The Ponderal Index is similar to BMI but uses the cube of height (kg/m³) instead of the square. It may be more accurate for very tall or very short individuals. Normal range is approximately 11–15 kg/m³.

Activity level is the most commonly mis-estimated variable. Most office workers are "Sedentary" (1.2×) or "Lightly active" (1.375×). Only those exercising hard 6–7 days per week qualify as "Very active". Try reducing your activity level by one step if results seem too high.

BMR can seem surprisingly low because it only accounts for calories burned at complete rest — no movement, no digestion, no walking to the kitchen. A 70 kg woman in her 30s might have a BMR around 1,400 kcal. This is normal. Your TDEE (which includes activity) will be 20–90% higher depending on how active you are. Use the TDEE Calculator to find your real daily needs.

Daily fat intake is calculated as a percentage of your Total Daily Energy Expenditure (TDEE). The Institute of Medicine recommends 20–35% of calories from fat. The formula is: fat grams = (TDEE × fat percentage) ÷ 9. Fat has 9 calories per gram — more than twice that of protein or carbohydrates. The LogiCalc Fat Intake Calculator handles this automatically once you enter your stats.

No. LogiCalc does not collect, transmit, or store any of the values you enter into our calculators. All calculations run entirely in your browser using JavaScript. Your age, weight, height, and other inputs never leave your device. The only data we collect is anonymous, aggregated traffic statistics via Google Analytics (no personal data).

All LogiCalc calculators support both metric (kg, cm) and imperial (lbs, ft/in) units. Use the unit toggle at the top of each calculator to switch between systems. Your preference is remembered for the session.

Standard metabolic calculators (BMR, TDEE, calorie targets) use equations validated for non-pregnant adults and are not accurate during pregnancy, when energy needs, weight distribution, and metabolic rate change significantly. LogiCalc is developing dedicated pregnancy nutrition tools. In the meantime, consult your OB/GYN, midwife, or a registered dietitian for calorie and nutrient targets during pregnancy.

Our BMR and TDEE calculators are designed for adults aged 18 and above. Children and adolescents have different metabolic rates and nutritional needs that require age-specific equations (such as the Schofield or FAO/WHO/UNU formulas for children). For a child's nutritional needs, consult a paediatrician or registered dietitian.

LogiCalc uses the same validated equations that registered dietitians and sports nutritionists use in clinical and performance settings — specifically Mifflin-St Jeor for BMR/TDEE, WHO BMI classification, and ISSN guidelines for protein. Results should be very close to what a professional would calculate from the same inputs. The key difference is that a dietitian also considers individual factors (medical history, medications, lab work, lifestyle habits) that no formula can capture.